Reverse Rotation Protection For Borehole Pumps

ABSTRACT

A reverse rotation protection for borehole pumps is disposed in a drive head. The reverse rotation protection includes a housing and a clamping tool for securing a polished rod. The clamping tool includes at least two exchangeable contact elements with which the polished rod can be fixed releasably.

FIELD OF THE INVENTION

The present invention relates to a reverse rotation protection for borehole pumps.

BACKGROUND OF THE INVENTION

Canadian patent CA 2 331 915 C discloses a device and a method for securing and holding a linkage in a borehole. The device is disposed beneath the skirt and above the borehole. The four holding elements for the linkage are disposed with an offset of 90°, so that each holding element holds the linkage from one side. The holding elements each comprise a clamping jaw and a screw, with which the clamping jaws are pressed against the linkage. When the clamping jaws lie adjacent to the linkage, a gap is present in each case between the individual clamping jaws.

Canadian patent CA 2 349 988 C describes a device for holding and fixing a polished rod in oil delivery pumps. The device is incorporated into the drive train of the crude oil pump and is connected to the latter by means of two flanges. For the fixing of the polished rod, two clamping jaws are pressed against the polished rod by means of threaded bolts. In the normal, non-clamped state, the clamping jaws are held apart from one another by springs and pressed against the inner wall of the device. A sleeve for guiding the polished rod is inserted into the lower region of the device.

SUMMARY OF THE INVENTION

The problem underlying the invention is to create a reverse rotation protection with which the drive train of a borehole pump can be secured against rotational movements when not in operation.

The above problem is solved by a reverse rotation protection according to the invention. Further advantageous embodiments can be found in the features of the sub-claims.

A reverse rotation protection for borehole pumps is disclosed, wherein the reverse rotation protection according to the invention is disposed in a drive head. The reverse rotation protection comprises a housing and a clamping tool for securing a polished rod. The clamping tool comprises at least two exchangeable contact elements with which the polishing rod can be fixed releasably.

The contact elements are each introduced releasably into a holding fixture. Each contact element is connected to the holding fixture by means of at least one screw. The contact elements are produced from a non-sparking and pressure-resistant material. The contact elements are preferably produced from bronze, brass or copper.

The clamping tool can be adapted to different polished rods with different diameters by means of contact elements differing in size. The contact elements with different internal diameters can be inserted into the holding fixtures of the clamping tool, so that different contact elements can be selected depending on the diameter of the various polished rods. It is clear to a person skilled in the art that, by means of different contact elements, the clamping tool can be adapted to polished rods which have changed their diameter during the operation of the borehole pump.

The side of the holding fixture lying opposite the contact element is provided with a groove for receiving a setscrew. The holding fixtures are movable inside the housing by means of the setscrews. Each setscrew is provided with a cap on the side facing away from the holding fixture. The caps are fitted on the setscrews when the contact elements are not in contact with the polished rod. It is thus possible to see that the borehole pump is ready for start-up. When the contact elements are in contact with the polished rod, the setscrews are screwed into the housing of the reverse rotation protection to an extent such that fitting of the caps on the setscrews is not possible. A further advantage of this approach is that the threads of the setscrews are protected by the caps against dirt and adverse weather effects during normal operation.

In a particular embodiment, the caps are provided with contacts which display the relaxation state of the reverse rotation protection. Furthermore, the caps are in contact, in each case via a connecting cable, with a control which prevents the borehole pump from starting up in the absence of a signal. This thus ensures that the borehole pump can only be started up when the contact elements are released from the polished rod and the latter is thus not blocked.

Furthermore, various process steps play a not inconsiderable role in protecting a borehole pump against undesired rotation of the drive train through reverse rotation. The contact elements are pressed against the polished rod, held against the polished rod and removed from the polished rod by means of actuating units. In preferred embodiments, setscrews or hydraulic actuating elements are used as actuating units. When the contact elements are removed from the polished rod, a contact is closed which releases the start-up of the borehole pump.

When use is made of setscrews, the release is brought about by contacts which are disposed in caps, which are screwed onto the setscrews after removal of the contact elements from the polished rod. In the case of the hydraulic actuating elements, this task can be performed by magnetic switches, which are moved by means of the hydraulically operated cylinder.

Examples of embodiment of the invention and its advantages are explained in detail below with the aid of the appended figures. The size ratios of the individual elements with respect to one another in the figures do not always correspond to the actual size ratios, since some forms are represented simplified and other forms, for the sake of greater clarity, magnified in relation to the other elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the position of the reverse rotation protection in the drive head.

FIG. 2 shows in detail the reverse rotation protection according to the invention.

FIG. 3 shows a perspective view of the reverse rotation protection.

FIG. 4 shows a reverse rotation protection with electronic start-up protection.

FIG. 5 shows in detail the protection system of a reverse rotation protection.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the position of reverse rotation protection 20 in drive head 10. Reverse rotation protection 20 is disposed in the upper region of skirt 14. Polished rod 12 runs through reverse rotation protection 20, as well as through drive head 10. Motor 18 is fitted on drive head 10 by means of bracket 16.

FIG. 2 shows in detail reverse rotation protection 20 according to the invention. Reverse rotation protection 20 comprises a housing 22. Clamping tool 24 for securing polished rod 12 is located in the interior of housing 22. In the embodiment illustrated here, clamping tool 24 comprises two holding fixtures 28, into which contact elements 26 are introduced. Contact elements 26 represent the connection between reverse rotation protection 20 and polished rod 12. Contact elements 26 are connected to holding fixtures 28 in a releasable manner by means of screws 30. Grooves 32, in which setscrews 34 engage, are provided in the sides of holding fixtures 28 lying opposite contact elements 26. Contact elements 26 are pressed against polished rod 12 or released from the latter by means of these setscrews 34. Caps 36 are disposed at the outer ends of setscrews 34. These caps 36 are fitted onto setscrews 34 when contact elements 26 are no longer in contact with polished rod 12 as a result of setscrews 34 being slackened off.

FIG. 3 shows a perspective view of reverse rotation protection 20. Holding fixtures 28 are introduced into housing 22. Contact elements 26, which are fixed releasably in holding fixtures 28 by means of screws 30, can be seen in the interior of holding fixtures 28. Furthermore, it is possible to see grooves 32 in which the setscrews (not represented) engage. Caps 36 can be seen at the outer side of housing 22, said caps covering setscrews 34 after removal of contact elements 26 from the polished rod (not represented). Caps 36 are connected to housing 22 by means of retention elements 37 in such a way that they cannot be lost when not in use.

FIG. 4 shows a reverse rotation protection 20 with an electronic start-up protection. In this example of embodiment, caps 36 are provided with contacts 38, which are connected by connecting cables 42 to a control 40. In this example of embodiment, control 40, like caps 36 too, is fitted to housing 22 of reverse rotation protection 20.

FIG. 5 shows in detail the protection system of reverse rotation protection 20 according to the invention. Setscrews 34 are disposed laterally in housing 22 of reverse rotation protection 20. The position of holding fixtures 28 and therefore contact elements 26 is changed with these setscrews 34. When contact elements 26 have been removed from the polished rod (not represented), setscrews 34 project beyond the housing part. If caps 36 are screwed onto setscrews 34, a connection is created between the heads of setscrews 34 and contacts 38. An electrical circuit is closed by this connection, which makes it possible to start the drive of the borehole pump.

The invention has been described by reference to a preferred embodiment. 

1. A reverse rotation protection for a borehole pump, wherein the reverse rotation protection is disposed in a drive head, wherein the reverse rotation protection comprises a housing and a clamping tool for securing a polished rod, characterised in that the clamping tool comprises at least two exchangeable contact elements, with which the polished rod can be fixed releasably.
 2. The reverse rotation protection according to claim 1, characterised in that the contact elements are each introduced releasably into a holding fixture.
 3. The reverse rotation protection according to claim 1, characterised in that each contact element is connected to the holding fixture by means of at least one screw.
 4. The reverse rotation protection according to claim 3, characterised in that the contact elements are produced from a non-sparking and pressure-resistant material.
 5. The reverse rotation protection according to claim 1, characterised in that the clamping tool can be adapted to diameters of different rods by means of contact elements of differing size.
 6. The reverse rotation protection according to claim 1, characterised in that the holding fixture is provided, on the side lying opposite the contact element, with a groove for receiving a setscrew.
 7. The reverse rotation protection according to claim 6, characterised in that the holding fixtures are movable inside the housing by means of the setscrews.
 8. The reverse rotation protection according to claim 1, characterised in that each setscrew is provided with a cap on the side facing away from the holding fixture.
 9. The reverse rotation protection according to claim 8, characterised in that the caps are fitted on the setscrews when the contact elements are not in contact with the polished rod.
 10. The reverse rotation protection according to claim 8, characterised in that the caps are provided with contacts, which display a relaxation state of the reverse rotation protection.
 11. The reverse rotation protection according to claim 8, characterised in that the caps are in contact, in each case via a connecting cable, with a control which prevents the borehole pump from starting up in the absence of a signal. 